All categories

3 years ago

BRAINLIEST

Chemistry

2 answers:

pogonyaev3 years ago

6 0

Answer:

1st opt.

(copper is the only material consisting of a single pure substance)

Explanation:

an element is made up of only one type of atom, and copper (Cu) as you can see is a single pure atom whereas salt (NaCl) and vinegar (C2H4O2) are both made of different elements.

Hope this helps

lesantik [10]3 years ago

5 0

Answer:

copper is the only material composed of a single pure substance

Explanation:

plss mark brainliest

You might be interested in

Which one of the following would you expect to dissolve in water? limonene sucrose oil atmospheric oxygen none of the above

sdas [7]

-----------sucrose----------------

3 0

4 years ago

Osmosis is the process responsible for carrying nutrients and water from groundwater supplies to the upper parts of trees. The o

Nady [450]

Answer:

0.825 M

Explanation:

The osmotic pressure is a colligative property, that can be calculated using the following expression.

π = M × R × T

where,

π is the osmotic pressure

M is the molarity

R is the ideal gas constant

T is the absolute temperature (24°C + 273 = 297 K)

M = π / R × T = 20.1 atm / (0.08206 atm.L/mol.K) × 297 K = 0.825 M

5 0

3 years ago

What is the theoretical yield of fluorenone if you oxidize 175 mg of fluorene?

My name is Ann [436]

Answer:

602 mg of CO₂ and 94.8 mg of H₂O

Explanation:

The yield is measured by the amount of each product produced by the reaction.

The chemical formula of fluorene is C₁₃H₁₀, and its molar mass is 166.223 g/mol.

The oxidation, also know as combustion, of this hydrocarbon is represented by the following balanced chemical equation:

$2C_{13}H_{10}+31O_2\rightarrow 26CO_2+10H_2O$

To calculate the yield follow these steps:

1. Mole ratio

$2molC_{13}H_{10}:31molO_2:26molCO_2:10molH_2O$

2. Convert 175mg of fluorene to number of moles

$175mg/times 1g/1,000mg=0.175g$

Number of moles = mass in grams / molar mass

$\text{number of moles}=0.175g/166.223g/mol=0.0010528mol$

3. Set a proportion for each product of the reaction

a) For CO₂

i) number of moles

$2molC_{10}H_{13}/26molCO_2=0.0010528molC_{10}H{13}/x$

$x=0.0010528molC_{10}H_{13}\times 26molCO_2/2molC_{10}H_{13}=0.013686molCO_2$

ii) mass in grams

The molar mass of CO₂ is 44.01g/mol

mass = number of moles × molar mass

mass = 0.013686 moles × 44.01 g/mol = 0.602 g = 602mg

b) For H₂O

i) number of moles

$0.0010528molC_{10}H_{13}\times10molH_2O/2molC_{10}H_{13}=0.00526molH_2O$

ii) mass in grams

The molar mass of H₂O is 18.015g/mol

mass = number of moles × molar mass

mass = 0.00526 moles × 18.015 g/mol = 0.0948mg = 94.8 mg

4 0

3 years ago

Night visin cameras are sensitive to energies around 2.21 x 10-19 J. What wavelength of electromagnetic radiation do they use?

defon

Answer:

8.99×10^-7m

Explanation:

The wavelength can be calculated using the expression below

E=hcλ

Where E= energy= 2.21 x 10^-19 J.

C= speed of light= 3x10^8 m/s

h= planks constant= 6.626 × 10^-34 m2 kg / s

E=hcλ

λ= E/(hc)

Substitute for the values

λ=( 2.21 x 10^-19 )/(6.626 × 10^-34 × 3x10^8 )

= 8.99×10^-7m

6 0

3 years ago

In a chemical reaction, the difference between the potential energy of the products of the potential energy of the reactants is

natka813 [3]

In a chemical reaction, the difference between the potential energy of the products and the potential energy of the reactants is equal to the heat of the reaction. This is, the net energy released or absorbed (change) during a chemical reaction is the sum of the potential energy of the products less the sum of the potential energy of the reactants.

3 0

4 years ago